Field of the Invention
The present invention relates to a solar battery-driven object detection system, in which a detection unit having a transmission unit and a reception unit is driven by the solar battery unit, the reception unit constantly receives detection beams transmitted from the transmission unit, and thereby detection of an object when the object intercepts the detection beams is achieved.
Description of Related Art
Object detection systems are thus far known that include a detection unit having a transmission unit such as a light projecting unit and a reception unit such as a light receiving unit which are arranged so as to oppose each other across a detection region, in which the light receiving unit constantly receives detection beams, for example infrared rays (IR), projected from the light projecting unit, to thereby detect an object when the object intercepts the infrared rays in the detection region. Such an object detection system is employed, for example, in a security sensor that outputs an alarm upon detecting an object.
In recent years, battery-driven object detection systems configured to supply power to the detection unit from a battery have come to be widely utilized, for purposes such as reducing power consumption and saving wiring works. Some of such object detection systems employ, for example, a solar battery unit including a solar panel for generating power using sunlight and a secondary battery for storing the power as disclosed in, for example, Japanese Laid-open Patent Publication No. 9-161157.
With the conventional solar battery-driven object detection system, however, the intensity of the detection beam has to be increased in order to extend the detection distance, and therefore a battery having a larger capacity has to be employed to cover the increase in power consumption, which leads to an increase in size of the solar panel to be incorporated. The increase in size of the system naturally results in an increase in cost. Meanwhile, with the solar panel of a reduced size, a sufficient battery capacity is unable to be secured and therefore the power consumption is limited, which makes it difficult to perform long distance detection since the detection distance is shortened.